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New member with a big climate control problem

Hi,

Hi!,

I'm a new guy and I need some help with my climate control system in my '98 328i. It's going nuts and rather than replace it I'd like to find out the real problem. Can anyone help??

What's hapening is that the entire electronic unit acts like it loses power while I'm driving, than it will kick back on and off. Sometimes just one or two light will stay on and the whole digital degree display will die. Just to let you know, mine has no dials or knobs. It's all digital with illuminated lights on buttons for A/C, front and rear defrost, temp increase & decrease, the AUTO button, etc. These are obviously part of the same circuit because they all go down at once and are all part of the climate control unit. Any help would be greatly appreciated.

I would start by simply checking the wiring harness at the back. You can access it by pulling out the storage space bellow and working your way up. The are all held in by expansion clips built into the plastic so just wiggle the units out.

Nope - you want to start from the bottom and work your way up. The computer comes out fairly easily once you get the hang of it. Again, there aren't any screws or anything, the tray, the computer and the climate control all pop out.

I tried to get out the compartment under the climate control but it didn't come out easy and i didn't want to force it. I noticed that there is a small hole on the top of the compartment and I was wondering if that is a lock release thing that, if properly pushed, will release the compartment. Anyone ever notice this??

Anyone else ever have this climate control problem??

Does anyone know what the decription of this thing is for the fuse box. I'd like to check the fuses and relays.

Comes out in a couple seconds. I used a flat head screwdriver to assist me. You dont need to take out the little sunglasses compartment. you just push up and back towards yourself through the hole you were talking about. Once i got the OBC to come out a little bit, i carefully used a flat-head screwdriver to assist in prying it out. weird, though, somehow the bulb behind the date/time burned out. you probably shouldnt do anything with the keys in Once i got the OBC out, the climate control was very easy to pop out.

It looks as the design flaw is actually on the circuit board of the CC unit. I took apart the plug (20 some pins) with all the wires coming from the car into the plug, nothing really happened. BUT when i put the plug in, if you push it a little on the long side of the plug, to the side, you can see it as it starts to kick in. as soon as you take the sideways pressure off the plug, it shuts off.
It is pretty easy to hear it kicking in, because with the OBC and CC units out, you can hear all the noises the fans and motors are making when they are working properly. I will be back in a few minutes to see what kind of semi-permanent solution i can come up with.

the solution BMW doesnt want you to know :)

ok, here is my quick fix. Seems to work great, hope it will last for a while.
this is engineering at its finest.

I broke me off a cigarette butt, folded it in half, and wrapped it with some electrical tape approx 4 times around. This gives me something that wasnt too hard/rigid, but by wrapping the electrical tape around it, I knew how thick it would be (it wont squish much more now. Then I wedged it in on the long side of the plug, just enough so it wont keep shutting off like it used to. the way you can tell how far to wedge this thing in is to push back lightly on the side of the plug opposite of where you put the makeshift wedge thingy and see if the Climate control shuts off again. if it doesnt shut off when you press lightly on it , it is fixed! (for now) I know it isnt the BMW $$$ way of doing it, but it works...

be careful, dont force anything. you dont want to break something, then you will definately have to buy the whole assembly. I will keep an update on this thread in a month or two to see if it holds up.

does this make sense? basically what i think happens is that over time, a connection where that plug receptor is soldered into the circuit board has been strained, and maybe has cracked just enough to lose contact. this is why this is such a common problem with these cars, and i'm willing to bet it's a more frequent problem on cars that do city driving and cars with loud subwoofers (vibrations)

of course, fixing it this way might mean that in another year or two it vibrates enough that you wil have to wedge it a little more. or maybe it will break all the way. all i know is that it's saving me $300+ for now

ok, on a side note...
Took a long drive today. CC unit worked great the whole time. Gotta love the german engineering. I always thought that it was dumb that you had to turn the know from blue to red in addition to setting the digital climate controls to high heat. The reason it's like that is because this way you can have heat blowing at your feet and cold air blowing on your face (without the windows open) if you have the knob set to blue while the heat is turned up.. Anyway, i'm sure you all know this already, but i just figured this one out, its pretty nice.

My DZCC unit crapped out about a year ago. You'll want to replace it. It's a design flaw in an electrical component, which one I'm not sure. Notice how ambient temperature effects the unit. When it's cold out, generally this electrical component (which I haven't yet identified) works great. Probably has to do with it contracting/expanding slightly with temperature. When the car gets warm, you'll find yourself out in the cold again as the CC turns off.

If it is repeatedly turning your fans on, off, I highly recommend uninstalling it right now. It could be causing stress on components. That loud CLUNK is not normal when the ventilation system reengages! Can't be good news.

Anyway, I snagged a new one on eBay for $150 about a year ago from a M3 converted to track duty.

Helluva job trying to come up with a way to fabricate a repair. I can't wait to try it myself. Let's keep this thread open for a while. You won't believe how many people are having this problem. On a side note, yesterday i noticed that the back o my dash (where the radio and CC electrical is) had a unbelievable amount of condensation on it. I also noticed that the plastic vents we extremely cold to the touch. So I checked under the hood and noticed that my A/C lines were heavily frosted......to the point where they actually turned WHITE! So i unplugged the module that connects into the condenser and magically my CC problems went away. Not the best fix, but I have a feeling that whatever malfunction we are having is causing the A/C to kick on, and the air isn't getting thru to the vents due to the CC malfunction. Also, the vibration is an excellent point....I just had a subwoofer put in not too long ago. Ironically, the sub woofer kicks on and off too along with the CC malfunction. Great job!

This is probably the best write-up yet of the description of this problem. Stang, you are exactly right. My A/C was doing the same thing.

Anyway, keep in mind this is a temporary fix for the C/C, not a complete fix. One day when I'm not busy at work I will take it back out, take it apart, and see if I can come up with a permanent fix without costing $$$.

I actually got the CC and the computer to pop out in less than 10 minutes last night, then it got dark. I will investigate further this weekend or possible Friday. When I went to work this morning it wouldn't even come on but I didn't notice anything loose when I checked back there last night. I think I'm going to try what you did and post my results to see if they are consistent with yours.

I had the same problem and spend over two week playing with that thing. It turned out to be a "cold solder" joint near the blue connector on the PCB board. I resolder all of the pins plus a few next to it and the problem went away for over six month now. Good luck

I'd appreciate it if you could post some pics cause I'm not very experienced at soldering. I'll give it a shot though. Can either of you describe in a little more detail exactly what pins you're referring to. My CC is still going crazy and I took the unit out but couldn't find the problematic pin.

You don't have to be good at soldering because all you need to do is re-flow the existing solder joints again. There is a coating on the PCB board that you may have to clean off first (just around the solder joint). My bad connection was actually the little blue rectangular capacitor next to the main 26 pin connector. My did the same repair to my friend 97 328is. If you look down at the board:

***************
* Blue connector *
* *************

****
**** blue rectangular capacitor

This capacitor is a line filter for the power to the board...this is why you get a on/off situation if you have a bad connection. As you can see I spend quite a bit of time researching this topic because the stealer want $600 for a recondition part and they have a back order of two months.

forget about my "simple fix" - after a couple days, the board flexed itself back and the problem started reoccurring.
anyway, i fixed that problem too. on mine it turned out to be a couple resistors and a SMT chip that was loose, but they are all in that same general area. I resoldered all of them. I bet there is a flaw with the manufacturing process, so even if you get a new one, you will have the same problem eventually again.

Mine has worked for a week now(since I fixed it) without a fault again.

I took some pictures. However, seeing hoanboy's post, the place that it needs to be resoldered changes from board to board. what I did was take it all apart, and then wiggle each piece with my fingers while it was plugged in to see which ones affected the problem. I took lots of pictures while dissasembling it also, this way you wont be so nervous about ripping it apart.

I disagree with hoanboy about not having to be good at soldering. It is entirely possible to overheat and melt another component on the board, or to solder two joints together that shouldn't be touching.

here's the steps of what I did. I dont have the cable that connects my camera to my computer with me, so the pictures wil have to wait.

1. disassemble the entire unit.
a. remove the unit from the dash as previously stated in this thread. unplug the connectors. be careful here. the big connector comes out by pressing down on a little plastic clip and then moving the white? lever over to push the whole plug out. the other small plugs just pry out easily with a flathead.
b. remove the four torx screws holding the thing together. you can use a thin, mediumsized flat head screwdriver to do this.
c. remove the two torx screws that hold the fan on. unplug the fan, take it out, and set it to the side.
d. there are two plastic snap things that hold the faceplate on. one is on the top, one is on the bottom. start on one side, press gently until it snaps out. then on the other side you have to squeeze two little plastic prongs together,push, and the whole faceplate pops out.
e. the circuit board that the display is on pops out very easily. just pry lightly on the top (the side above the display) and it will pop out.
f. The board that this is connected to is much more difficult to remove. using your medium flathead, stick it in against the right or left side. you will see the the circuit board is notched just enough to fit a screwdriver in between the circuit board and the plastic cover. go back and forth on each side, prying a little more out at a time on each side. soon it will all come out.
g. you are left with the two circuit boards attached to each other by two ribbon wires. Then i plugged that little fan thing back in after it was all apart.

2. go back to the car and plug it in again (start the car to get power to it). it will be hooked up and function fine, except that it is out of the case.

3. look on the board on the area around the blue connector and start putting a little pressure/wiggling on each component. Take your time, and see if by pressing on a component you can get the thing to start working again.

4. once you have located the suspected bad connection, shut the car down, go back inside and get out the soldering iron.

5. heat up/melt the coating directly around the component you need to resolder. scrape away the rest of that orangish stuff with a tiny flathead screwdriver or something. scrape lightly so you do not damage the green board underneath.

6. when you see the solder joints shining silver instead of orange... coat them with the solder flux. solder flux can help even an inexperienced solderer do a much cleaner job.

7. take your hot soldering iron, stick the tip on the conection to be soldered, feed in a tiny bit of solder, and in a second, the new connection should be shiny and clean. if you hadn't used flux here, you would have had a much harder time getting the solder to stick properly. this also helps ensure that the solder doesnt actually boond with two close-by joints. repeat this on all needed joints.

8. take your circuit boards back to your car, and repeat step 3 - if you cannot get anything to trigger the display to fault out again, then you have solved the problem. if it still has issues, then wiggle some more pieces and repeat steps 4-8 until it does not occur again.

hope this really helps. sorry about the other "quick fix" for anyone who actually tried doing that.

Listen, i am thinking. anyone who is too queasy or inexperienced to do this themselves, i would be glad to do it for them for a small fee + shipping. It does take a couple hours to do it properly, and i would guarantee a fully functioning unit or your money back. seriously, there is no reason to go back to BMW and pay $300+ for a new unit, that will have the same problem again a couple years down the road.

I have my climate control unit out and I am pressing on the componants but nothing seems to be working consistantly. The only consistant way to get it to turn on and off is to wiggle the big blue plug or bend the board slightly on the end the plug is on. I have inspected the board and do not see any bad solder connections. I also need to know where to buy the replacement bulb for the OBC. Please help

I haven't had the CC act up on me since this posting. I'm actually happy but it's really odd. I don't drive the car in the cold weather and I think that the cold weather had something to do with it. I think the dealer is your source for the bulb. I'm ignoring the fact that is used to act up on me and I guss I'll takew action when and if it starts again. Good luck!

bamablue - check your email, i sent you a detailed message on what i think you should do. for everyone else reading this who might run into the same problem, i think that the reason bamablue is not able to pinpoint the source of the bad connection is that there is more than one bad connection. on mine i had to resolder a couple different things before i finally got it to work properly and consistently. (notice my instruction step 8)

BTW, to this day, since my fix, still no reocurring climate control problems for me

Stang, i think you are correct somewhat... as it gets cold, it contracts slightly, causing the connections to be more skewed. when the weather warms back up, it might expand and work again (for a while at least!!)

All people with e36 cars need to save this thread somewhere because it is not if you have had the prob it is when. I took the board to a guy who runs a audio/ video repair shop. I told him what I had found out from researching mainly this thread. He took the board and did his best to examine the board under his lighting and high powered viewing lens. He was not able to see a damn thing because of the coating that is put on the board. What he did was resolder the connector. He heated each of the 26 pins with his gun. As he did that, it melted the coating and the solder at the same time so he was not able to tell whether or not he had done any good or not. I took the board to my car and checked it out in his parking lot. I was not able to get it to cut out at all so I knew that he had fixed it. I went to the dealer to get the bulb and was shocked to hear that that tiny ass bulb costs three dollars and something a piece. I asked him while I was there about the climate control unit and he said that this year they have installed 10 of the units in cars. He had one in stock and it would only set me back $311 plus tax. These forums are worth every minute you spend on them if you use them as a helping tool. None of this would have been possible without Robp074. Thanks man.